Disposable biosensors conventionally used are those obtained by applying a reagent containing an enzyme and a mediator to an electrode system disposed on a base material and forming a capillary to draw a liquid sample thereinto using a spacer and a cover (e.g., Patent document 1). The application of voltage to the biosensor enables the concentration measurement of a substance to be measured in a sample based on a diffusion current by the mediator.    [Patent document 1] Japanese Patent No. 2901678